<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no">
    <title>mobile-shop</title>
  </head>
  <body>
    <div id="app"></div>
    <script type="text/javascript">
      let htmlWidth = document.documentElement.clientWidth || document.body.clientWidth
      if(htmlWidth>=750) htmlWidth =750;
      let htmlDom = document.querySelector('html');
      htmlDom.style.fontSize = htmlWidth/20+'px';
    </script>
  </body>
</html>
